以顺时针方向运行指依从时针移动的方向运行（如右上图），即可视为由右上方向下，然后转向左，再回到上。数学上，在直角坐标系以方程序x = sin t 和 y = cos t 定义的圆形，随着t值减少所代表的曲线就是依顺时针方向绘画。换一种说法，当你不断向你的右方移动，也是循着顺时针方向移动。顺时针的相反方向是逆时针方向。

一旋转运动属于顺时针抑或逆时针，视乎观察面的设置。例如，由北极正上方看下去，地球自转属于逆时针，但由南极正上方看下去，地球自转则是顺时针。

Circular motion can occur in two possible directions. A clockwise (typically abbreviated as CW) motion is one that proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite sense of rotation or revolution is (in Commonwealth English) anticlockwise (ACW), or (in North American English) counterclockwise (CCW). In a mathematical sense, a circle defined parametrically in a positive Cartesian plane by the equations x = cos t and y = sin t is traced counterclockwise as t increases in value.